Refrigerator and method for controlling same

ABSTRACT

The present invention relates to a refrigerator and, more specifically, a refrigerator which enables a user to easily open a door thereof. The present invention relates to a refrigerator and method for controlling the same, which can prevent a door thereof from opening by itself due to a malfunction. According to an embodiment of the present invention, a refrigerator may comprise: a cabinet having a storage chamber; a door for closing or opening the storage chamber; a sensor provided to sense whether a user is within or out of a sensing distance, to enable discrimination between sensing-on and sensing-off; a door opening device provided to automatically open the door; and a control unit for determining an operation condition of the door opening device on the basis of a time interval from the sensing-on to the sensing-off and a duration for which the sensing-on continues in the sensor, so as to control the operation of the door opening device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage application under 35 U.S.C. § 371of International Application No. PCT/KR2017/012445, filed on Nov. 3,2017, which claims the benefit of Korean Patent Application No.10-2016-0145898, filed on Nov. 3, 2016. The disclosures of the priorapplications are incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a refrigerator, and more particularly,to a refrigerator in which a user is capable of easily opening a door ofthe refrigerator. The present invention relates to a refrigerator, inwhich a door of the refrigerator is prevented from being automaticallyopened by a malfunction, and a method for controlling the same.

BACKGROUND ART

Refrigerators are household appliances that are capable of store objectssuch as foods at a low temperature in a storage chamber provided in acabinet. The storage chamber is surrounded by heat insulating wall sothat the inside of the storage chamber is maintained at a temperatureless than an external temperature. The storage chamber may be referredto as a refrigerating compartment or a freezing compartment according toa temperature range of the storage chamber.

A user open and close the storage chamber through a door. The user opensthe door to put the object into or out of the storage chamber. Ingeneral, the door is rotatably provided on the cabinet, and a gasket isdisposed between the door and the cabinet. Thus, in a state in which thedoor is closed, the gasket is closely attached between the door and thecabinet to prevent cold air within the storage chamber from leaking. Asthe closely attaching force of the gasket increases, the cold airleakage prevention effect may increase.

To allow the closely attaching force of the gasket to increase, thegasket may be provided as a rubber magnet, and a magnet may be providedin the gasket. However, when the closely attaching force of the gasketincreases, it means that large force as much as the closely attachingforce is required to open the door.

In recent years, a refrigerator having an auto closing function is beingprovided. The auto closing function means a function of automaticallyclosing the door of the refrigerator when the door of the refrigeratoris slightly opened by using the closely attaching force of the gasket,magnetic force, and elastic force of a spring. Also, the auto closingfunction means that the door of the refrigerator does not open by itselfeven when the refrigerator is slightly tilted forward.

Thus, the refrigerators provided in recent years require much more forceto open the door when compared to the previous refrigerators. This isdone because it is necessary to overcome the closely attaching force,the magnetic force, and the elastic force so as to open the door of therefrigerator.

For example, the user may need force of 6 kgf to open the door of therefrigerator. Since this force is relatively large, it is impossible toeasily open the door. Also, a problem may arise that the door is rapidlyopened because very large force is applied to open the door.

To solve this problem, a refrigerator has been proposed in which a doorof the refrigerator is capable of being automatically opened.

For example, a refrigerator has been proposed in which a door of therefrigerator is automatically opened when a user pushes a specificbutton, or a door is automatically opened when a user touches or drags aspecific area.

For example, a refrigerator has been proposed in which a door isautomatically opened by sensing approach of the user' body when theuser's body or a portion of the user's body approaches a specificposition of the refrigerator.

However, the refrigerator according to the related art has a problemthat the door is automatically opened even if the user does not intendto do so. For example, the door may be automatically opened if the usersimply passes through the front of the refrigerator or if the usersimply leans against the door of the refrigerator. In this case, theuser may be surprised or hurt by the opening of the door, and clod airmay be lost if the opening of the door is maintained. That is, unlikethe user's intension, the door may be unnecessarily opened to cause thesafety problem and the cold loss.

DISCLOSURE OF THE INVENTION TECHNICAL PROBLEM

A basic object of the present invention is to solve the problem of theabove-described refrigerator according to the related art.

An embodiment provides a refrigerator that is easily used by reducinguser's force required for opening a door of the refrigerator

An embodiment provides a refrigerator in which a door of therefrigerator is easily opened while maintaining closing force of thedoor of the refrigerator.

An embodiment provides a refrigerator in which a door of therefrigerator is easily opened while maintaining an auto closing functionof the refrigerator door.

An embodiment provides a refrigerator in which a door of therefrigerator is automatically opened by clearly understanding user'sintension of opening the door of the refrigerator.

An embodiment provides a refrigerator which is capable of preventing adoor of the refrigerator from being automatically opened even though auser does not intend to open the door of the refrigerator.

An embodiment provides a refrigerator which is intuitively used by auser to automatically open a door of the refrigerator without grasping ahandle of the door by a hand.

An embodiment provides a refrigerator in which a user does not need totouch a button or a sensor so as to automatically open a door. Thus, arefrigerator, which is capable of automatically opening a door thereofeven when a user holds an object in both hands, and a method forcontrolling the same are provided.

An embodiment provides a refrigerator which is capable of preventing adoor of the refrigerator from being opened by a malfunction through acontrol method without adding a new configuration.

An embodiment provides a refrigerator which is capable of effectivelyopening one door through one door opening device and a method forcontrolling the same.

An embodiment provides a refrigerator which is capable of effectivelyopening a plurality of doors through one door opening device and amethod for controlling the same.

An embodiment provides a refrigerator in which a user is capable ofeasily selecting a specific opening mode in the refrigerator having aplurality of door opening modes and a method for controlling the same.

An embodiment provides a refrigerator in which a user intuitivelyunderstands which door opening mode is performed to open a door throughnotification and a method for controlling the same.

An embodiment provides a refrigerator in which malfunction conditions ofa door opening device are sequentially removed and a method forcontrolling the same. For example, conditions such as a case in whichthe door opening device operates in the state in which the door isopened, a case in which the user passes through the front of therefrigerator, or a case in which the user is located in the front of therefrigerator for a long time are sequentially removed.

Technical Solution

To realize the above objects, according to an embodiment of the presentinvention, a refrigerator comprises: a cabinet having a storage chamber;a door configured to open and close the storage chamber; a sensorconfigured to sense whether a user is within or out of a sensingdistance to distinguish sensing-on and sensing-off from each other; adoor opening device configured to automatically open the left and rightdoors; and a control unit configured to determine a driving condition ofthe door opening device on a basis of a sensing-on duration time and atime interval till the sensing-off after the sensing-on so as to controlthe driving of the door opening device.

When the sensing-on duration time is less than a preset time (t1), thecontrol unit may determine that the driving condition is not satisfied.As a result, when the user is passing by the refrigerator, the dooropening device may not operate.

When the sensing-on duration time is greater than a preset time (t1),the control unit may determine whether the sensing-off is performed.

When the sensing-off is not performed during a preset time, the controlunit may determine that the driving condition is not satisfied. As aresult, when the user or an object is located at the front of therefrigerator for a long time, the door opening device may not operate.

When it is determined that the sensing is off, if a time spent for thesensing-off after the sensing-on is less than a preset time (t1+t2), thecontrol unit may determine that the driving condition is satisfied.

The preset time (t1) may correspond to a time for which the user intentsto open the door and maintain access to the door, and the preset time(t2) may be determined corresponding to a time for which the user is outof the door to form an opening space of the door. Thus, the malfunctionof the door opening device may be prevented in stages.

The refrigerator may further comprise a notification device, wherein thenotification device may operate before the door is opened.

When the sensing-on duration time is equal to or greater than the presettime (t1), the control unit may control an operation of the notificationdevice so that the user is notified that the door is scheduled to beopened.

The refrigerator may further comprise a door switch configured to sensewhether the door is opened or closed, wherein the control unit maydetermine whether the driving condition of the door opening device issatisfied when the closing of the door is sensed by the door switch.

To realize the above objects, according to an embodiment of the presentinvention, a method for controlling a refrigerator comprises: performingsensing-on to sense whether a user is within a sensing distance througha sensor; performing primary determination to primarily determine thatthe user intends to open the door when a sensing-on duration time isequal to or greater than a preset time (t1); performing sensing-off tosense whether the user is out of the sensing distance through the sensorafter the primary determination; performing secondary determination tosecondarily determine that the user intends to open the door when a timespent for the sensing-off after the sensing-on is less than a presettime (t1+t2); and performing door opening by driving a door openingdevice after the secondary determination to automatically open the door.

After the primary determination, if the sensing-off is not performed fora preset time (t3), the operation may be returned to the sensing-onafter the sensing-off is performed.

The sensing-on may comprise initializing a time to count a time afterthe sensing-on.

After the primary determination, notification may be performed to notifythat the door is scheduled to be opened to the user is performed.

After the notification, the sensing-off may be performed.

The method may further comprise performing door opening determination todetermine whether the door is opened or closed through a door switch.

In the door opening determination, when it is determined that door isclosed, the sensing-on may be performed.

To realize the above objects, according to an embodiment of the presentinvention, a method for controlling a refrigerator comprises: performingsensing-on to sense whether a user is within a sensing distance througha sensor; performing primary determination to primarily determine thatthe user intends to open the door when a sensing-on duration time isequal to or greater than a preset time (t1); performing notification todrive a notification device and notify that the door is scheduled to beopened to the user is performed after the primary determination;performing sensing-off to sense whether the user is out of the sensingdistance through the sensor after the notification; and performing dooropening by driving a door opening device to automatically open the doorafter the secondary determination.

The notification may comprise confirming the intension of the user onceagain to open the door, rather than simply notifying that the door isscheduled to be opened to the user. This is done because the user has tomove for the sensing-off through the notification. Due to the movement,the user's intension to open the door may be more clearly confirmed.

The notification device may comprise a buzzer that generates a beepsound. That is, the notification device may be a device for generatingsound.

The method may further comprise performing door opening determination todetermine whether the door is opened or closed through a door switch.

In the door opening determination, when it is determined that door isclosed, the sensing-on may be performed.

Advantageous Effects

The embodiment may provide the refrigerator that is easily used byreducing the user's force required for opening the door of therefrigerator

The embodiment may provide the refrigerator in which the door of therefrigerator is easily opened while maintaining the closing force of thedoor of the refrigerator.

The embodiment may provide the refrigerator in which the door of therefrigerator is easily opened while maintaining the auto closingfunction of the refrigerator door.

The embodiment may provide the refrigerator in which the door of therefrigerator is automatically opened by clearly understanding the user'sintension of opening the door of the refrigerator.

The embodiment may provide the refrigerator which prevents the door ofthe refrigerator from being automatically opened even though the userdoes not intend to open the door of the refrigerator.

The embodiment may provide the refrigerator which is intuitively used bythe user to automatically open the door of the refrigerator withoutgrasping the handle of the door by the hand.

The embodiment may provide the refrigerator in which the user does notneed to touch the button or the sensor so as to automatically open thedoor. Thus, the refrigerator, which is capable of automatically openingthe door thereof even when the user holds the object in both hands, andthe method for controlling the same may be provided.

The embodiment may provide the refrigerator which is capable ofpreventing the door of the refrigerator from being opened by themalfunction through the control method without adding the newconfiguration.

The embodiment may provide the refrigerator which is capable ofeffectively opening the one door through the one door opening device andthe method for controlling the same.

The embodiment may provide the refrigerator which is capable ofeffectively opening the plurality of doors through the one door openingdevice and the method for controlling the same.

The embodiment may provide the refrigerator in which the user is capableof easily selecting the specific opening mode in the refrigerator havingthe plurality of door opening modes and the method for controlling thesame.

The embodiment may provide the refrigerator which is capable ofintuitively understanding whether the user opens the door in any dooropening mode through the notification and the method for controlling thesame.

The embodiment may provide the refrigerator in which the malfunctionconditions of the door opening device are sequentially removed and themethod for controlling the same. For example, conditions such as a casein which the door opening device operates in the state in which the dooris opened, a case in which the user passes through the front of therefrigerator, or a case in which the user is located in the front of therefrigerator for a long time are sequentially removed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a refrigerator that is applicable to anembodiment of the present invention;

FIG. 2 is a perspective view of a door illustrated in FIG. 1 ;

FIG. 3 is a plan view illustrating an example of an operation of a dooropening device that is applicable to an embodiment of the presentinvention;

FIG. 4 is a plan view illustrating another example of the operation ofthe door opening device that is applicable to an embodiment of thepresent invention;

FIG. 5 is a plan view illustrating further another example of theoperation of the door opening device that is applicable to an embodimentof the present invention;

FIG. 6 is a block diagram of a control configuration that is applicableto an embodiment of the present invention;

FIG. 7 is a flowchart illustrating a control method that is applicableto an embodiment of the present invention;

FIG. 8 is a conceptual view of a refrigerator that is applicable toanother embodiment of the present invention; and

FIG. 9 is a flowchart illustrating a control method according to anotherembodiment of the present invention.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will bedescribed with reference to the drawing.

FIG. 1 is a perspective view of a refrigerator that is applicable to anembodiment of the present invention. For example, a structure in whichtwo doors that open and close an upper refrigerating compartment and twodoors that open and close a lower freezing compartment are provided isillustrated.

The refrigerator according to an embodiment of the present invention maycomprise a cabinet 10 having a storage chamber and a door 12 provided onthe cabinet 10. The storage chamber defined by the cabinet may be openedand closed through the door 12. Thus, the refrigerator may have an outerappearance defined by the cabinet 10 and the door 12.

Since a user uses the refrigerator at a front side of the refrigerator,the door is disposed on the front of the refrigerator.

For example, a refrigerating compartment door 13 for opening and closingthe refrigerating compartment 111 may be provided. The refrigeratingcompartment door 13 may be constituted by left and right doors 15 and14. Also, a freezing compartment door 16 for opening and closing thefreezing compartment 112 may be provided. The freezing compartment door16 may be constituted by left and right doors 18 and 17.

The door 12 may be provided to be rotatable through a door hinge 114.That is, the door 12 may be provided to be rotatable with respect to thecabinet through the door hinge 114.

The user may grasp the door 12 to open and close the door. For this, ahandle is provided on the door. In FIG. 1 , an example in which handles14 a, 15 a, 17 a, and 18 b are respectively provided on the doors 14,15, 17, and 18 is illustrated.

That is, when the user intends to open the door, a hand of the user isintuitively accessed to the handles. Also, the user grasps the handlesto apply force for pulling the door. Embodiments of the presentinvention may be provided to improve user's convenience by using theuser's intuitive operation.

FIG. 2 is a perspective view of the door illustrated in FIG. 1 . Forconvenience of description, the left refrigerating compartment door 14is illustrated.

Embodiments of the present invention may comprise a door opening device25 that automatically opens the door. That is, a device forautomatically opening the door through an electric motor may beprovided. As illustrated in FIG. 2 , the device may be provided in thedoor. On the other hand, the device may be provided in the cabinet.

The door opening device 25 is driven in preset conditions or states. Thedoor opening device 25 is driven to automatically open the door. Thus,user's force required for opening the door may be significantly reduced.Alternatively, a sensor for determining the preset condition or state isnecessary. The sensor will be described later.

FIGS. 3 to 5 illustrate examples of the door opening device 25 that isapplicable to an embodiment of the present invention. Particularly, anexample in which the door opening device is provided at the door 14 isillustrated. Also, a structure in which the door opening device isdisposed on a top surface of the door is illustrated. That is, anexample in which the door opening device 25 is mounted on a cap decoportion of the door is illustrated.

Hereinafter, each of the door opening devices 25 will be described indetail.

The door opening device 25 comprises a housing 26. At least one or moregears 28 may be accommodated in the housing 26. The gears 28 operate bydriving of a motor 26. The rotation of the motor 26 that rotates at ahigh speed may be decelerated through the gears 28. At least a portionof the motor 26 may be accommodated in the housing 26.

The housing 26 may be provided to be fixed to the door 14. The housing26 may be mounted on a top surface of the door 14, and then, a cap decor(not shown) may cover the top surface of the door 14. Thus, mostconstituents of the door opening device including the housing 26 may bemounted in the door 14 so as to be protected from the outside.

The motor 26 is driven to open the door 14. Here, the gears 28 may alsobe driven by the driving of the motor 26. The driving force of the motor26 may be transmitted to a rack 29 through the gears 28.

The rack 29 may be a constituent provided to protrude from the housing26. That is, the rack 29 may be a constituent protruding from thehousing and having a variable protruding length.

FIG. 3 illustrates a configuration in which the rack 29 furtherprotrudes to the outside of the housing 26 to further protrude to theoutside of the door 14. Thus, as the rack 29 increases in protrudinglength, the rack 29 may apply force so that the door 14 is away from thecabinet 10. On the other hand, in the state in which the door 14 isclosed, the protruding length of the rack 29 may be minimized. That is,it is preferable that a length of the rack 29, which protrudes to theoutside of the door 14, is minimized.

Here, the protruding length of the rack 29 may be proportional to anopening angle of the door 14. This is done because, when the door 14rotates by using the door hinge 114 as a center, the rack 29 ismaintained to contact the cabinet 10. However, as described below, sincethe contact position between the rack 29 having a linear shape and thecabinet 10 varies, the protruding length of the rack 29 and the openingangle of the door 14 may not be directly proportional to each other.

The increase of the protruding length of the rack 29 is limited. Thatis, an increase of an angle at which the door is automatically opened islimited. This is done because the protruding length of the rack 29 isnot greater than a length of the rack 29. Also, this is done because thelength of the rack is not greater than a front/rear width of the door14, i.e., a thickness of the door.

Alternatively, the rack 29 may pass through the door 14 in forward andbackward directions. However, in this case, a problem of design may becaused very seriously. Also, the exposure of the rack 29, which moves tothe front of the refrigerator, may cause not only a design problem butalso that the overall door opening device becomes complicated.

The rack 29 linearly moves. That is, in the state in which the door isclosed, the rack 29 and the cabinet 10 are disposed to perpendicular toeach other. However, as the angle at which the door is opened increases,an angle between the rack 29 and the cabinet 10 may vary. This meansthat a portion on which the rack 29 and the cabinet 10 contact eachother moves.

Thus, a distal end of the rack 29 may be worn, or a portion of thecabinet, which contacts the distal end of the rack 29, may also be worn.

FIG. 4 illustrates a shape in which the door opening device 25 describedin FIG. 3 is improved.

Although the rack 29 described in FIG. 3 linearly moves, the dooropening device 25 may move in a curved shape. That is, otherconstituents are the same, but only a shape of the rack 29 is different.

The rack 29 may have a curved shape on the whole. Alternatively, thedistal end of the rack 29 may be a straight line shape, and only aportion contacting the gear 28 may have a curved line shape. The curvedline may have a constant radius with respect to the door hinge 114.

The rack 29 may protrude with a constant radius with respect to the doorhinge 114. That is, when the motor 26 is driven, the rack 29 mayprotrude from the door 14 to push the cabinet 10. Thus, the proportionalrelationship between the protruding length of the rack 29 and theopening angle of the door 14 may be satisfied. Therefore, the rack 29having the curved shape rather than the rack 29 having the linear shapemay be used to relatively increase in opening angle of the door.

Also, a contact position between the rack 29 and the cabinet 10 may bealways constant. Thus, problems that may occur as the contact positionis changed in the state in which the rack 29 and the cabinet 10 contacteach other may be solved.

However, it may be difficult to manufacture the rack 29 having thecurved shape, and manufacturing cost may increase. Also, the curved lineof the rack 29 has to be mounted to have a constant radius with the doorhinge 114. That is, if the mounted position is not accurate, variousproblems may occur. Thus, the mounted position may be very limited, andalso, vary accurate mounting may be required.

FIG. 5 illustrates a shape in which the door opening device 25 describedin FIG. 3 is improved.

Although the rack 29 described in FIG. 3 linearly moves, the dooropening device 25 may diagonally move. That is, other constituents arethe same, but only a shape of the rack 29 is different.

Particularly, the rack 29 illustrated in FIG. 3 may have a shape thatprotrudes at an angle that is perpendicular to the door 14. However, inthe door opening device 25, the rack 29 may have a shape that protrudesat an angle that is diagonal with respect to the door 14. That is tosay, the rack 29 illustrated in FIG. 3 moves in the same direction asthe thickness direction of the door 14. However, the rack 29 accordingto this embodiment may move in a direction that is tilted with respectto the thickness direction of the door 14.

Thus, in this embodiment, the rack 29 may have a length that is furthergreater than the thickness of the door 14. That is, this means that theprotruding length of the rack 29 further increases. Thus, the angle atwhich the door is automatically opened may more increase.

In the above-described door opening devices, the opening angle of thedoor may increase according to the protruding length of the rack. Thus,when the rack maximally protrudes, the opening angle of the door may bemaximized. However, thereafter, the user holds the handle to more rotatethe door. Thus, the door opening devices may provide force for openingthe door up to an automatic opening angle of the door. However, when thedoor is initially opened, relatively large force may be required, andthus, the user may very conveniently open the door.

Hereinbefore, embodiments of the door opening device that is capable tothis embodiment have been described. However, the door opening devicehaving various shapes without being limited to the above-describedembodiments may be applied to this embodiment. For example, the dooropening device mounted on the cabinet rather than the door may beapplied. Also, for example, the door opening device of which both doorsare opened rather than the door opening device of which only one door isopened may be applied.

Hereinafter, a control configuration of the refrigerator according to anembodiment of the present invention will be described in detail withreference to FIG. 6 .

A sensor 115 senses user's intension for opening the door. In thisembodiment, the sensor 115 may be a distance sensor or a human bodysensor instead of a sensor that is directly pressed or touched by theuser. That is, as illustrated in FIG. 1 , the sensor 115 may be mountedon the front surface of the refrigerator. Thus, the sensor 115 may sensethat the user approaches the refrigerator.

Since the sensor 115 is not touched by the user, the user need notperform a special operation. That is, the user have only to simplyapproach the refrigerator. Thus, it may be very effective when it isdifficult to open the door due to objects held in both hands or when aseparate touch is difficult.

When the user's approach is sensed by the sensor 115, and it isdetermined that the user intends to open the door, the control unit 110may control an operation of the door opening device 25 to automaticallyopen the door.

The sensor 115 may be provided to sense whether the user is within orout of a sensing distance. The former may be sensing-on and the lattermay be sensing-off.

A time for which the sensing-on is continuous may be counted in thesensor 115. Also, a time for which the sensing-off is continuous afterthe sensing-on is continuous may be counted. The user's door openingintension may be clearly determined on the basis of the counted times.That is, a case in which there is no user's door opening intention maybe distinguished to prevent the door from being opened by a malfunction.

In this embodiment, a door switch 200 and a notification device 300,which are control configurations of the general refrigerator may beprovided. The door switch 200 may be a configuration for simplydetermining only opening and closing of the refrigerator. When theopening of the door is sensed in the door switch 200, a lighting devicewithin the storage chamber may be turned on, and when the closing of thedoor is sensed in the door switch 200, the lighting device may be turnedoff.

Also, when the door of the refrigerator is opened for a predeterminedtime or more, a notification sound or a beep sound may be generated inthe notification device 300, for example, a buzzer. That is, thenotification sound may alert the user to the attention.

It is seen that the control configuration illustrated in FIG. 6 is notso different from the control configuration of the general refrigerator.However, an embodiment of the present invention may provide arefrigerator, which is capable of significantly reducing the malfunctionof the door through the sensor 115 that senses the user's approach, anda control method.

Hereinafter, a control method of the refrigerator according to anembodiment of the present invention will be described in detail withreference to FIG. 7 .

In an initial operation or a starting operation (S10) may be performed.That is, preparation for driving the door opening device may beperformed.

To open the door, whether the user intends to open the door has to bedetermined. In this embodiment, the approach of the user to therefrigerator may be primarily determined that the user intends to openthe door. This is done because the opening of the door is based on theapproach of the user to the refrigerator.

Thus, in this control method, the sensing-on (S30) may be performed todetermine whether the user is within the sensing distance through thesensor 115. It may be said that a first condition for door opening issatisfied until the sensing-on is performed.

However, it may be that the user does not approach the refrigerator toopen the door, but just to pass by the refrigerator. Thus, in this case,it is preferable that the door has not to be opened. In this case, atime for which the sensing-on is continuous in the sensor may berelatively less.

Thus, to prevent this malfunction from occurring, the primarydetermination (S40) may be performed. That is, the primary determinationfor determining whether the user truly intends to open the door may beperformed. In the primary determination (S40), the sensing-on durationtime may be compared to a preset time t1.

When the sensing-one duration time is greater than the preset time t1,it may be primarily determined that the user intends to open the door.The preset time t1 may be a relatively short time for which the userpasses by the refrigerator. Thus, when the sensing-on is continuous forabout 1 second or more, it may be primarily determined that the userintends to open the door.

The user may perform other operations in the front of the refrigeratorwithout intending to open the door. For example, the user may clean thefront of the refrigerator or stand on the refrigerator. In this case, itis preferable that the door of the refrigerator is not automaticallyopened.

Due to the characteristics of the refrigerator, a predetermined distancefrom the user has to be maintained to open the door. In the use of thegeneral refrigerator, the user may be spaced a predetermined from therefrigerator and then hold the door of the refrigerator to open thedoor. Also, the user may more approach the refrigerator to take foodsout of the storage chamber. Thus, when the user opens the door, the userintuitively know that the door has to be maintained at a predetermineddistance from the refrigerator.

In consideration of the use pattern of the refrigerator, the user maymove to be spaced a predetermined distance from the refrigerator so asto open the door of the refrigerator. That is, after the user approachesthe refrigerator, the user may be disposed at a position that is alittle further away from the refrigerator to open the door of therefrigerator.

In consideration of this, it is preferable that secondary determination(S70) is performed after the primary determination. That is, it isdetermined whether the user moves to secure a space for opening thedoor. This moving time is not relatively long. Thus, in this case, itmay be determined that the user is willing to open the door before thepresent time elapses after the first determination.

If the preset time elapses so that the sensing-off is performed, theuser may determine that the user performs cleaning or the like withoutintending to open the door as described above. Thus, when thesensing-off (S70) is not performed during the preset time t3, thesensing-on (S30) may be returned after the sensing-off.

Here, the time counting may be performed continuously and may beperformed step by step. In FIG. 7 , an example in which the timecounting is continuously performed from the sense-on to the secondarydetermination (S80) is illustrated. For this, resetting (S20) ofresetting the time before the initial operation, i.e., the sensing-on isperformed may be performed. Alternatively, the resetting (S20) may becomprised in the sensing-on (S30).

After the sensing off (S70) is performed, when the sensing-off isperformed before the preset time (t1+t2) added with the sensing-offduration after the sensing-on duration elapses, the secondary dooropening intention of the user may be confirmed.

Thus, the opening (S90) of the door by driving the door opening devicemay be finally performed through the confirmation (S80) of the secondarydoor opening intention of the user.

The control method may be performed based on the case in which the dooris closed. Thus, determination (S15) of determining whether the door isclosed may be performed as the premise of the determination ofdetermining an opening condition of the door.

The determination (S15) may be performed through the door switch. Thus,when the opening of the door is determined through the door switch,unnecessary operations may be previously prevented from being performed.

The control method may comprise notification (S50 and S60) of previouslynotifying the opening of the door to the user. That is, the notification(S50 and S60) may be performed to notify that the door is scheduled tobe automatically opened or that the door opening device is scheduled tooperate.

The notification may be also referred to as a signal that the user isaway from the door because the door is scheduled to be opened. Also, thenotification may be referred to as a signal for confirming the user'sintention to open the door. When the notification is ignored, and theuser does not move, the condition of the subsequent secondarydetermination (S80) may not be naturally satisfied.

Here, when the notification (S50 and S60) are performed, the secondarydetermination (S80) may be omitted, and the door opening (S90) may beperformed. That is, when the sensing-off (S70) is performed after thenotification, the door opening may be immediately performed.

The notification may be an operation of generating sound such as beepsound. That is, the notification device may be provided as a buzzershape generating the beep sound. Thus, even though the user's gazeleaves the refrigerator, the user may hear what is happening in therefrigerator through the auditory sense. That is, the user mayintuitively know that the door of the refrigerator is automaticallyopened by listening the beep sound.

As described above, the user's door opening intention may be clearlyunderstood to prevent the door from being malfunctioned. Also, this maybe achieved through the control without additional configuration.

Also, according to the foregoing embodiment, the door opening devicethat opens one door may be controlled without the malfunction.Furthermore, that the door opening is scheduled may be notified to theuser through the notification such as the beep sound to secure asufficient space for opening the door.

The malfunction of the door opening device may be caused not only in thedoor opening device that opens one door but also in the door openingdevice that opens two doors.

For example, the malfunction may also occur in a case in which two doorsopening and closing one storage chamber are provided on left and rightsides. The malfunction may occur when each of the doors is opened byusing a separate door opening device as well as when the doors areopened through one door opening device.

FIG. 8 illustrates a concept in which two doors are opened through onedoor opening device. For example, a concept in which left and rightdoors 15 and 14 are opened through one door opening device 45 disposedon the top surface of the cabinet 10.

In this embodiment, the sensor 115 may be similarly provided. The sensor115 may be a sensor for sensing whether the user approaches therefrigerator as described above.

Thus, the same problem as described above may occur in the refrigeratorin which the left and right doors are opened through one door openingdevice. Particularly, even when the door opening intention of the useris determined through one sensor 115, the same problem such as themalfunction of the door opening device may occur.

Hereinafter, an embodiment of a control method for solving the problemin the refrigerator illustrated in FIG. 8 will be described in detail.The configuration required in this embodiment may be the same as that inthe foregoing embodiment. However, the door opening device according tothis embodiment is different from the door opening device according tothe foregoing embodiment in that two doors but not one door are opened.For example, FIG. 8 illustrates two racks 49 for respectively openingthe left and right doors in one door opening device. Thus, duplicateddescription with respect to the same characteristic as the foregoingembodiment will be omitted.

Since a refrigerator in which two left and right doors or a plurality ofdoors are automatically opened is provided, an opening mode of the doorsmay be provided in plurality. That is, structures in which the pluralityof doors are opened may be different from the plurality of door openingmodes.

For example, the plurality of door opening modes may comprise an openingmode in which only any door is opened. Also, the plurality of dooropening modes may comprise an opening mode in which all the doors areopened.

Also, in the case of the left and right doors that open one storagechamber, the left door may be opened in a first mode, and the right doormay be opened in a second mode. Of course, vice versa may be possible.Also, in the first mode, one of the left door and the right door may beopened, and in the second mode, all of the left and right doors may beopened.

In this embodiment, the user may select the plurality of door openingmodes while preventing the door from being automatically opened againstthe user's intention.

As illustrated in FIG. 8 , the initial operation (S100) for opening thedoor may be performed, and whether the door is opened may be determined(S110) through the door switch. When it is determined that the door isclosed, whether the condition for the door opening is satisfied may beperformed at last.

When the sensor 115 determines whether the user approaches therefrigerator (S130), and the sensor 115 senses that the sensed value iswithin a threshold value, i.e., when the user is sensed to be within thesensing distance of the sensor, the sensor may determine that the sensoris in the sensing-on. Here, primary determination (S140) in which thesensing-on duration time is compared with a preset time T1 is performed.

Here, the preset time T1 is a time for checking whether the userapproaches the refrigerator with the door opening intension. Thus, forexample, if the user maintains the approach for 1 second or more, whichis the preset time T1, it may be primarily determined that the userintends to open the door. Alternatively, if the user is only sensed fora very short time to pass through the refrigerator, it may be returnedto the initial operation. As a result, the opening of the door due tothe malfunction may be prevented.

In the embodiment, the operations S100 to S140 may be the same those inthe foregoing embodiment.

In this embodiment, as in the forgoing embodiment, an operation (S210)of secondarily determining the door opening intention of the user may beperformed. Basically, the secondary determination (S210) is similar tothe secondary determination (S80) according to the foregoing embodiment.

However, in this embodiment, a plurality of opening modes in which theplurality of doors are opened may be provided. Thus, an operation ofdetermining which mode has to be performed before the secondarydetermination may be performed.

In FIG. 9 , for example, the plurality of door opening modes may bedivided into an operation (S190) of performing the first mode as an A1mode and an operation (S240) of performing the second mode as an A2mode.

Here, the plurality of doors may be opened in different forms in thefirst mode and the second mode, and also, the user may select the modes.For example, the user may select the modes so that the left door isopened in the first mode, and the right door is opened in the secondmode. On the other hand, the user may select the modes so that the rightdoor is opened in the first mode, and the left door is opened in thesecond mode. Also, the user may select the modes so that the right dooris opened in the first mode, and all of the left and right doors areopened in the second mode. Thus, the form in which the doors are openedaccording to the plurality of modes may satisfy the user's preference bythe user's selection.

After the primary determination (S150), the sensing-off (S180) may beperformed. After the primary determination (S150), a time spent untilthe sensing-off (S180) is performed may be counted. That is, when thedoor opening intention of the user is confirmed in the primarydetermination (S150), the user may move away from the refrigerator. Thatis, to secure the opening space of the door, the user may move slightlyaway from the refrigerator. Here, when the spent time is less than apreset time T2, it may be determined that the first mode is selected.That is, first mode selection (S160) may be performed.

In the selection (S160), only whether the first mode is selected may bedetermined. When it is determined that the first mode is selected, anoperation (S190) of driving the door opening device according to thefirst mode may be performed. Also, whether the user intends to finallyopen the door is not determined in the selection (S160).

The user may move away from the refrigerator a little longer. That is,in the selection (S160), the first mode may not be selected. That is,when the sensing-off is performed within the preset time T2 in theselection (S160), the sensing (S200) may be performed again through thesensing sensor. Here, the secondary mode selection (S210) may beperformed again. The secondary mode selection (S210) may be an operationof determining whether the second mode is selected. Also, the secondarymode selection (S210) may be an operation of secondarily determiningwhether the user intends to open the door. That is, the secondary modeselection may be an operation of selecting the secondary mode andfinally determining whether the user intents to open the door.

In the secondary mode selection (S210), when the sensing-off (S230) issensed within a preset time T3, it may be determined that the userselects the secondary mode. Also, when the sensing-off (S230) is notsensed during the preset time T3, it may be finally determined that theuser does not intent to open the door. In this case, It may be said thatthe user is cleaning in front of the refrigerator or simply leaning onthe refrigerator.

Thus, in this embodiment, similarly to the foregoing embodiment, it mayfinally confirm the user's intention to open the door on the basis ofthe time spent for the sensing-off after the sensing-on. When the timeis finally longer than the sum of the times T2 and T3, the door may beprevented from automatically opening.

Also, the time taken from the sensing-on to the sensing-off may bedivided into two sections. For example, when the sensing-off isperformed within 1 second after the sensing-on, the first opening modemay be determined to be selected in the preceding section. Also, whenthe sensing-off is performed within 1 second and 2 seconds after thesensing-on, it may be determined that the second opening mode isselected. Alternatively, when the sensing-off is performed after 2seconds, it may be finally determined that the user does not intent toopen the door.

Thus, a desired mode of the plurality of door opening modes may beselected through the two operations (S160 and S200) that are performedafter the primary determination. These operations may be referred to asthe secondary determination.

Thus, in this embodiment, the door opening mode may be selected on thebasis of the different in time, for example, the difference in timespent from the sensing-on to the sensing-off. Thus, the door openingmode may be selected very effectively and intuitively.

In this embodiment, notification may be performed as in the foregoingembodiment. That is, the scheduled opening of the door and the scheduledoperation of the door opening device may be previously notified.

Here, the notification may be an operation of notifying which mode thedoor is opened. That is, different types of notification may beperformed depending on the mode.

To perform the first mode, notification (S170) of ringing a beep soundonce and notification (S220) of ringing a beep sound twice may beperformed to perform the first mode. Thus, the user may intuitivelyunderstand which mode the door is opened through the notification (S170and S220) that are distinguished from each other.

FIG. 9 sequentially illustrates the operations S160 to S180. However,this operations may not be sequentially performed but performed at thesame time. Also, the notification (S170) may be performed after theoperation S180. The operations S210 to S230 may be the same.

INDUSTRIAL APPLICABILITY

According to the embodiment of the present invention, since therefrigerator that is easily used by reducing the user's force requiredfor opening the door of the refrigerator is provided, the industrialapplicability is remarkable.

The invention claimed is:
 1. A refrigerator comprising: a cabinetincluding a storage chamber; a door configured to open and close thestorage chamber; a sensor configured to sense whether a user is withinor out of a sensing distance; a door opening device configured toautomatically open the door; and a control unit that is configured todetermine a driving condition of the door opening device based on asensing-on duration time of a sensing-on operation and that isconfigured to control driving of the door opening device, wherein thecontrol unit is further configured to: based on determining that theuser is within the sensing distance through the sensor, determinewhether the sensing-on duration time is greater than or equal to a firstpreset time, based on the sensing-on duration time being greater than orequal to the first preset time, control a notification device togenerate a sound to notify that the door is scheduled to be opened,based on the notification device generating the sound, determine whethera sensing-off operation is performed, based on determining that thesensing-off operation is performed within a second preset time after thesensing-on operation is performed, operate the door opening device toautomatically open the door, and based on determining that thesensing-off operation is not performed within the second preset time,determine that the driving condition of the door opening device is notsatisfied.
 2. The refrigerator of claim 1, wherein the control unit isconfigured to, based on the sensing-on duration time being less than thefirst preset time, determine that the driving condition is notsatisfied.
 3. The refrigerator of claim 1, wherein the first preset timecorresponds to a time for which the user intends to open the door andmaintain access to the door, and wherein the second preset timecorresponds to a time for which the user is outside of a turning rangeof the door to form an opening space of the door.
 4. The refrigerator ofclaim 1, wherein the notification device comprises a buzzer configuredto generate a beep sound.
 5. The refrigerator of claim 1, furthercomprising a door switch configured to sense whether the door is openedor closed, wherein the control unit is configured to, based on the doorswitch sensing that the door is closed, determine whether the drivingcondition of the door opening device is satisfied.
 6. The refrigeratorof claim 1, wherein the door opening device comprises: a motor; and apush rod disposed between a hinge of the door and the motor andconfigured to be driven by the motor.
 7. The refrigerator of claim 6,wherein the push rod is configured to, being driven by the motor, pushthe cabinet to thereby open the door.
 8. The refrigerator of claim 6,wherein the push rod includes a rack gear that has a curved shape andthat defines a constant radius with respect to the hinge.
 9. Therefrigerator of claim 1, wherein the sensing-on operation includesdetecting a presence of the user within the sensing distance, andwherein the sensing-off operation includes detecting an absence of theuser within the sensing distance.
 10. The refrigerator of claim 9,wherein the sensing-off operation further includes detecting a movementof the user away from the door within the sensing distance.
 11. A methodfor controlling a refrigerator including a door, the method comprising:determining whether a user is within a sensing distance through asensor; performing a primary determination to primarily determine thatthe user intends to open the door based on a sensing-on duration time ofa sensing-on operation being equal to or greater than a first presettime; after the primary determination, operating a notification deviceto generate a sound to notify that the door is scheduled to be opened;determining whether the user is out of the sensing distance through thesensor after operating the notification device; performing a secondarydetermination to secondarily determine that the user intends to open thedoor based on a sensing-off operation being performed within a secondpreset time after the sensing-on operation is performed; and performingdoor opening by driving a door opening device after the secondarydetermination to automatically open the door.
 12. The method of claim11, further comprising: after the primary determination, determiningwhether the sensing-off operation is not performed for a third presettime after the sensing-on operation is performed; and based ondetermining that the sensing-off operation is not performed for thethird preset time, determining whether the user is within the sensingdistance after determining whether the user is out of the sensingdistance.
 13. The method of claim 11, wherein determining whether theuser is within the sensing distance comprises initializing a time countafter the sensing-on operation is started.
 14. The method of claim 11,further comprising performing a door opening determination to determinewhether the door is opened or closed through a door switch.
 15. Themethod of claim 14, wherein the door opening determination is performedbased on determining that the door is closed.